Pump impeller and method of assembling



Patented Mar. 7, 1939 UNITED STATES PATENT OFFICE PUMP IMPELLER AND METHOD OF ASSEMBLING ware . Application September 20, 1938, Serial No. 230,772

3 Claims.

This invention relates to centrifugal pump, and more particularly to impellers therefor and a method of mounting such impellers on their driving shafts.

In pumps employed in handling various types .of acids in the chemical and allied industries,

corrosive and/or abrasive conditions necessitate the use of a high silicon iron or other hard, nonmachinable alloy or ceramic material in the pump construction, and liquid-tight connection between the high silicon iron impeller and its steel driving shaft to prevent the acid pumped from contacting the shaft.

Various methods have been employed for connecting the impeller and shaft, such as casting a -high silicon iron impeller on the shaft, as dispermit replacement of the impeller when it be-- comes worn, without requiring an entirely new shaft and impeller assembly, The present struc-'- ture also effectively prevents the liquid being pumped from contacting the steel shaft and provides a rigid, solid connection between the impeller and shaft.

With these and other objects in ,view, as may appear from the accompanying specification, the

invention consists of various-features of construction and combination of parts, which will be first described. in connection with the accompanying drawing, showing a pump impeller and method of assembly embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawing:

Figure 1 is a longitudinal section through the improved impeller assembly.

Figure 2 is a cross-section through the impeller assembly taken on the line 2-2 of Figure 1.

Figure 3 is a cross-section taken on' the line 33 of Figure 1. 1

Figure 4 is an isometric'view of the shaft.

Referring more particularly to the drawing, the impeller proper comprises the disk In having the pumping blades ll formed thereon, the hub I2, and a sleeve l3 which is formed integrally with the hub l2 and projectsaxially therefrom. The sleeve I3 is made longer than the pump casing (not shown) so that the end of the sleeve 5 will project out of the casing to prevent the liquid being pumped from entering the sleeve.

The impeller hub I2 is provided with a bore M which is smaller in diameter than the bore l5 of the sleeve l3. The bore l4 opens into the bore 10 [5 of the sleeve l3, and into a recess l6 formed in the hub. The recess l6 has its circular con- The width of the head I9 is equal to the width of the elongated bore l4 formed in the hub so that in assembling the shaft and impeller the head I!) will pass through the elongated bore l4 in the hub and thus into the recess 16, after which the shaft is rotated to bring the sides of the head It] at opposite ends thereof into engagement with the abutment surfaces I8; to provide a firm solid metal to metal contact between the head IS on the shaft and the impeller abutment surfaces [1. The abutment surfaces H are positioned so that the metal contact between the head I9 on the shaft and the impeller is in the direction of rotation of the shaft and impeller, whereby transmission of the driving torque is provided in the direction of pumping rotation of the impeller.

The elongated opening M in the hub l2 has the same contour as the recess l6, as illustrated by Figures 2 and 3, except that it is displaced angularly by a suitable amount so that when the shaft 20 is inserted in the impeller bore and rotated by a corresponding amount the'head I9 moves under the projecting shoulders 24 formed by the elongated opening l4 and locks the impeller against axial movement. Thus any axial thrust 'due to the operation of the pump is transmitted directly by metal to metal contact from'the impeller to the shaft. Thus none of the operating forces are transmitted through the cement or bonding agent.

The shaft 20 is cemented in the impeller by the filling of the spaces around the head ill in the recess l6 and around the neck M of the shaft which serves to connect the head H to the main body of the shaft 20; Such cement is shown at 22. By particular reference to Figures 1 and 3 of the drawing, it will be noted that the diameter of the'neck 2 I is less than the width of the elongated opening [4 in the hub I2, and also that the head 9 is smaller than the recess I6, so as to provide ample space for receiving a sufficient quantity' of cement to thoroughly and securely connect the shaft 20 and impeller III in a rigid 'structure practically the equivalent of a unitary structure.

The cement employed may be any suitable type of cement or lead alloy to provide a sufficient and secure bond between the shaft 2|] and impeller [0. If an alloy is used, a suitable amount of the alloy can be placed in the recess I6 and the impeller heated until the alloy is molten. The shaft can then be inserted and turned as described above. On cooling the alloy will solidify and firmly bond the impeller to the shaft.

In assembly, a sufficient quantity of this cement or bonding agent, in liquid form, is poured into the recess I6, after which the shaft is inserted into the sleeve l3, with the head l9 extending into the recess Hi. This forces the cement upwardly, filling all of the spaces about the head l9 and neck 2|. The cement or bonding agent is then allowed to harden, after which the impeller is ready for service.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. In a pump structure, an impeller, a shaft therefor, a coupling head on said shaft, said impeller provided with a recess receiving said coupling head, said recess shaped to provide abutment surfaces and shoulders for engagement with the head to prevent withdrawal of the head from the recess after the shaft has been turned a partial turn subsequent to the insertion of said coupellerl provided with a recess receiving said coupling head, a bonding agent in said recess about said head for securely connecting said shaft and impeller, driving surfaces on said, head, abutments formed in said recess for engagement with said driving surfaces to provide metal to metal contact between the shaft and impeller for transmission of driving torque in the direction of pumping rotation of the impeller. 3. In a pump structure, a pump impeller, shaft therefor, a sleeve on the impeller for receiving the shaft, a section of the shaft near its impeller engaging end having a reduced diameter, a coupling head formed on the end of the reduced portion of the shaft, said sleeve having an interior diameter greater than the diameter of the shaft, and a reduced section corresponding to the reduced section of the shaft shaped to allow passage of the coupling head 'therethrough,

said impeller having an enlarged recess opening into said reduced section to receive said coupling head and allow the shaft to be turned therein to'alocked position, and a bonding agent about the coupling head and fillingthe space surround- GEORGE F. HABACH. 

